This invention relates to a system for the diagnosis of flow related problems which may exist in implantable medication delivery devices. Those implantable flow devices include continuous pumps, programmable pumps, and ports. Typical is the INFUSAID Series 100 and 400 devices and INFUSE-A-PORT ports. The evaluation of in-vivo pump performance requires obtaining and monitoring measured flow data and pump system environmental conditions at various intervals. One typical time of determining performance of the in-vivo system is during refill of the pump wherein measured flow rates to the expected in-vivo port performance requires obtaining and monitoring catheter flow resistance.
There are a variety of problems which may cause variations in such performance. For example, in-vivo pump temperature may differ from the assumed constant body core temperature. This will effect the pump flow by varying the 2-phase vapor pressure of the pressurizing material, typically Freon. Variation in in-vivo pump temperature may also vary the viscosity of the medication. Another parameter that effects pump flow is the presence of any resistance at the catheter tip.
In the case of sideport access systems such as the INFUSAID 400, it is possible to separate a diagnosis of pump operating parameters from those of the catheter. A determination of the separate flow problems for the pump and catheter are important since a malfunctioning pump would not require recatheterization and a malfunctioning catheter would not require a pump explant. Thus, in situations where the in-vivo device utilizes a sideport, either integral or separate, diagnosis of catheters attached to the pumps can be used to measure the pressure at the inlet to the catheter. In those systems, then, a requirement exists to differentiate pump flow problems from catheter flow problems.
In the past, fluoroscopic examination of the catheter in a blood vessel, while injecting a contrast agent, has been attempted as a technique to determine the presence of any resistant elements at the catheter tip. Such visual techniques, however, do not provide sufficient information to fully evaluate catheter performance.